The role of nighttime predation in suppressing soybean aphid populations

The soybean aphid, Aphis glycines, infests soybeans across the Midwestern and Northeastern United States, often causing economic losses and causing growers to rely on insecticides. In some instances, natural enemies are able to provide substantial control of soybean aphid, but the factors influencing the abundance and diversity of natural enemies in soybean fields remain poorly characterized. Studies in natural systems and our preliminary data suggest that plant genetic diversity can play a large role in structuring insect communities. We are exploring the potential of crop genotypic diversity for enhancing natural enemy communities in crop fields. To understand the influence of genetic diversity on natural enemy populations in soybeans, we conducted a large field experiment with genetically simple and genetically diverse plots. Within these plots, we characterized the community of potential soybean-aphid predators and partitioned their roles further by using exclusion cages to differentiate between day and night time predation and by sampling at night to capture ground-dwelling predators that forage in the foliage at night. Our results appear to indicate that increasing crop genetic diversity holds promise as an insect pest management strategy.